"There is a lot of confusion and anxiety from the public at large over what power they have on the information that is collected," he said. He said there is worry that information put together for profiles that "may be incorrect ... out of context" and long lasting could do far more than provide ads. It could potentially lead to problems getting jobs or higher health care insurance.

The committee's chairman, Sen. Jay Rockefeller, D-W.Va., said when he discussed the issue of the hearing with his family, family members all kicked in with concerns.

"The consumer I am concerned about is not a savvy computer whiz-kid. ... I'm talking about a 65-year-old man who just signed up for a Facebook account so he can view photos of his grandson, and reconnect with old friends. We have a duty to ask whether these people -- and the millions of Americans just like them -- fully understand and appreciate what information is being collected about them, and whether or not they are empowered to stop certain practices from taking place," he said.

The Senators comments came as the committee heard from government officials, researchers and officials of Apple, AT&T, Google and Facebook about profiling of users, through tracking of their information.

While much of the profiling is done anonymously, Joseph Turow, a professor at the Annenberg School of Communications at the University of Pennsylvania, told the committee that the profiling starts to question the traditional definition of "anonymous."

"The industry claims of anonymity undermine the traditional meaning of anonymity," he said. "If they know I'm Joseph Turow or 'XXXX3,' it doesn't matter if they are following me around the Web."

He also said national studies say Americans don't understand the amount of tracking and behavioral profiling taking place.

Industry executives answered that they have taken strong steps to protect privacy. Facebook's Chief Technology Officer Bret Taylor said privacy is a consideration in every new choice for Facebook.